Vacuum tube electrode



Oct. 31, 193.3. F. HAFECOST 1,933,109

VACUUM TUBE ELECTRODE Filed March 26, 1930 Patented Oct. 31, 1933 PATENT OFFICE 1,933,109 VACUM TUBE ELECIRODE Frederick Hafecost, Brooklyn, N. Y., assignor to Goat Radio Tube Parts, Inc., Brooklyn, N. Y., a corporation of New York Application March 26, 1930. Serial No. 439,027

2 Claims.

This invention relates in general to improvements in electrodes for vacuum tubes, such as audions as used in radio apparatus.

More particularly the invention is directed to 5 the so-called screen grid of a screen grid audion.

One of the objects of this invention is the provision of a screen grid electrode of this type which is exceedingly simple in structure, easy to manufacture, and adapted for rapid and cheap reproduction of quantities.

A urther object of this invention is the con struction of a screen grid which is exceedingly strong, mechamcafly, which is neat in appearance, and adapted for uniform manufacture.

A further object of this invention is the provision of an electrode of this type which may be constructed without the necessity of welding the parts together.

These and other objects, as will appear from the following disclosure, are secured by means of this invention.

This invention resides substantially in the combination, construction, arrangement, and relative location of parts, ail as will be described below.

Referring to the drawing Figure 1 mis a top plan view of one form;- of 1electrode made in accordance with this inven- Fig. 2 is a cross-sectional view taken on the line 2 2 of Fig. 1;

Fig. 3 is a cross-sectional view through the cylindricai body of the electrode at the seam;

Fig. 4 is a top plan view of a modifled form of electrode;

Fig. 5 is a cross-sectional view taken on the line 5-5 01 Fig. 4; and

Fig. 6 is a section through the seam on the cylindrical body.

At the present time it is usual to make the screen grid as used in screen grid audions of a mesh or perforate material in the form of a cylinder open at both ends and to then fit in one end a metal dise to close it and finally to we1d it in place. This method of construction is exceedingly crude and is not adapted to rapid and accurate manufacture of the electrodes in large quantities. In addition the eiectrodes as now constructed are relatively expensive and are not regular and uniform. There is considerable difliculty encountered in placing the end plate in proper position within the end of the cylindrical body and welding it in place. As a result the grids as now made are expensive, must be made by hand, and are not uni1orm in shape and as strong as they might be. When the cylinder is a. mesh grid the wire ends are exposed at the dise.

One form of electrode as constructed in accordance with this invention is shown as comprising in Figs. 1 to 3, inclusive, a cyiindrical body member 1 joined along a longitudinal lineto complete the cylinder by means of a double seam 2.

The cylindrical body member is perforated with ca1ly and electrically. The center of the dise is punched out as at 7 and small tabs 8 are struck up by means of which the electrode is mounted upon suitable supports within the audion.

The modified form in Figs. 4 to 6, inclusive, only difiers from the form previousiy described in that the main cyIindrical body portion 10 is made of wire mesh or screen. The 1ower edge of the screen is doubled b ack on itseif, as shown at 14, to give a smooth finished edge, such as a reinforced one. The other end is flared out, as shown at 12, in a manner t0 fit with the bead 6 on the top 5, and need not be nished, reinf0rced, or selvedged, because it is protectively received and housed by the channel of the top dise.

By means of this construction the electrode may be made truly cylindrical and the end disc 5 may be accurately and firmiy secured in place. without welding. By means of the construction employed the electrode is exceedingIy strong even rated sheet shown in Figs. 1, 2, and3, or the wire mesh or Woven sheet shown in Figs. 4, 5, and 6. The term cylinder is understood to apply to an electrode, whether circular in cross section or not.

What I seek to secure by United States Letters Patent is:

1. A vacuum tube electrode comprising a perforate sheet metal cylinder, and a. metal plate or closure member the surface of which s shaped to form a peripheral shoulder and an edge fiange, the outermost portion of the edge being reversely bent upon tself to form a channel, one end of the cylinder beng received and protective1y housed by the aforesaid channel, and said channel being compressed t0 securely clinch and grip the cylinder to form a complete unitary electrode.

2. A vacuum tube electrode comprising 3. perforate sheet of metal rolled into the form of a cylinder, one end of said cylinder being flared FREDERCK HAFECOST. 

